Casei Gerola is a comune (municipality) in the Province of Pavia in the Italian region Lombardy, located about 60 kilometres (37 mi) southwest of Milan and about 25 kilometres (16 mi) southwest of Pavia.
Casei Gerola borders the following municipalities: Bastida de' Dossi, Castelnuovo Scrivia, Cornale, Isola Sant'Antonio, Mezzana Bigli, Molino dei Torti, Pontecurone, Silvano Pietra, Voghera.
It was part of the Counties of Guastalla and, later, county of Montechiarugolo, both ruled by the Torelli family, until 1612. It remained to the Torelli until 1797.
- ^ All demographics and other statistics: Italian statistical institute Istat.